Centrifugal casting machine



v. GHIORZO ETAL 3,358,745

CENTRIFUGAL CASTING MACHINE Dec. 19, 1967 Filed Nov. 27, 1964 2 Sheets-Sheet l Smkh fim Y 0 #W E T a N N MR E60.M O V x 6 w W Fr A MN Dec. 19, 1967 v. GHIORZO ETAL 3,358,745

CENTRIFUGAL CASTING MACHINE Filed Nov. 27, 1964 2 Sheets-Sheet 2 INVENTORS V/TTJF/O 6/9/0220 ff/M65560 Gil/0,920

flab-ATTORNEY United States Patent 3,358,745 CENTRIFUGAL CASTING MACHINE Vittorio Ghiorzo and Francesco Ghiorzo, both of 328 W. 44th St, New York, N.Y. 10036 Filed Nov. 27, 1964, Ser. No. 414,148 Claims priority, application Italy, Nov. 27, 1963, 24,695/63; Dec. 7, 1963, 25,254/63 5 Claims. (Cl. 164-289) ABSTRACT OF THE DISCLOSURE A driven horizontal shaft of the centrifugal casting machine carries a radially extending casting arm which supports a crucible and a mold whose cavity communicates with the chamber of the crucible. A torch is mounted on the casting arm to heat the charge in the chamber of the crucible when the arm is idle as well as when the arm rotates. The torch receives oxygen and acetylene through a single conduit having a fixed section which is coaxial with the driven shaft and a second section which is rotatably connected with the fixed section and delivers fuel to the torch.

The present invention relates to casting machines in general. Still more particularly, the invention relates to an improved centrifugal casting machine which is especially suited for use by jewelers for casting platinum, palladium, silver, gold, wax and other materials.

A centrifugal casting machine comprises an elongated casting arm which resembles a balance beam and is rotatable about a fixed axis. One leg of the casting arm carries a crucible whose chamber receives a charge of material to be melted and this one leg also carries a mold which is outwardly adjacent to and whose cavity communicates with the chamber of the crucible. The other leg of the casting arm carries a counterweight. The casting machine further comprises, a mot-or, normally a spring type motor whose spring may he rewound to store energy and, when the arm is released to rotate about its fixed axis while the spring unwinds, molten material flows from the crucible into the mold cavity to form a shaped article. The charge which is introduced into the chamber of the crucible is heated to melting temperature by a jewelers torch whose flame is directed against the charge and which is held by hand but must be removed or ejected from the path of the casting arm just before the latter begins to rotate. Thus, the charge can be heated only while the casting arm is idle. It happens again and again that the charge hardens prior to complete transfer into the mold cavity so that the casting is unsatisfactory and must be remelted, or the ultimate product is one of less than perfect shape.

Accordingly, it is an important object of the present invention to provide an improved centrifugal casting machine which is constructed and assembled in such a way that the charge in the crucible may be heated not only prior to rotation of the casting arm but also while it is subjected to the action of centrifugal force and flows into the mold cavity.

Another object of the invention is to provide a novel arrangement for heating the charge in the crucible of a centrifugal casting machine.

A further object of the invention is to provide a centrifugal casting machine wherein an oxyacetylene flame may act upon and prevents cooling of the charge in the crucible while the casting arm of the machine rotates at a high speed to effect transfer of molten charge into the mold cavity.

Still another object of the invention is to provide an improved winding device for the drive of a centrifugal 3,358,745 Patented Dec. 19, 1967 casting machine and to provide a very simple and reliable locking device which prevents rotation of the casting arm during charging and during melting of the contents of the crucible.

A concomitant object of the invention is to provide a centrifugal casting machine wherein certain component parts of the heating arrangement simultaneously perform an additional function and replace such part or parts which are essential for satisfactory operation of conventional centrifugal casting machines.

Another object of the invention is to provide a very simple, compact and easy-to-operate centrifugal casting machine which may be produced and assembled at reason able cost, which may be utilized with advantage in melting of a large number of widely different metallic or nonmetallic materials, and which may be readily accommodated in a small area.

A further object of the invention is to provide a centrifugal casting machine wherein the heating device may be installed or removed as a unit.

Briefly stated, one feature of our invention resides in the provision of a centrifugal casting machine, particularly a machine for use by jewelers for casting precious metals and other materials used in connection with the manufacture of jewelry. In its elementary form, the machine of our invention comprises drive means including a rotary output member which is arranged to rotate about a fixed axis, for example about a horizontal axis, a casting arm secured to and having a leg extending substantially radially with reference to the output member, a composite mold fixed to the leg at a point distant from the output member and having a cavity arranged to receive a supply of molten material so that such material may harden and then forms an article of jewelry or the like, a crucible fixed to the leg intermediate the mold and the output member and having an open-sided chamber communicating with the mold cavity and arranged to receive a charge of material to be melted so that, upon heating to melting temperature, the charge enters the mold cavity by centrifugal force in response to rotation of the output member which drives the arm, and heating means including an oxyacetylene torch or another suitable heating element mounted on and rotatable with the leg. The heating element is mounted sufliciently close to the open side of the chamber to heat the charge to melting temperature while the leg is idle and to continue such heating when the shaft rotates to cause expulsion of molten charge into the mold cavity. Thus, the machine of our invention is equipped with heating means adapted to maintain the charge in molten condition not only when the arm is idle but also when the output member rotates the arm whereby the charge in the crucible remains in molten condition to insure complete filling of the mold cavity.

In accordance with a more specific feature of our invention, the heating element may be mounted at the end of a conduit which supplies oxygen and acetylene, and this conduit includes a fixed section which is coaxial with the output member and a second section which connects to the heating element. The two sections are coupled by a joint which allows the second section to rotate about the axis of the fixed section. The fixed section is connected to a source of oxygen and to a source of acetylene.

Alternatively, the two sources may be mounted on a second leg of the casting arm so as to constitute a counterweight when the casting arm rotates. The connection between the two sources and the heating element then comprises a single conduit which may extend along the arm and on to that portion of the first leg Where the heating element is mounted in close proximity to the crucible.

The novel features which are considered as characteristic of the invention are set forth in particular in the appended claims. The improved casting machine itself, how- 3 ever, both as to its construction and the mode of assembling and operating the same, together with additional features and advantages thereof, will be best understood upon perusal of the following detailed description of certain specific embodiments with reference to the accompanying drawings, in which:

FIG. 1 is a perspective View of a centrifugal casting machine which is constructed in accordance with a first embodiment of our invention;

FiG. 2 is an enlarged fragmentary front elevational view of a portion of the machine shown in FIG. 1 and illustrates in detail the mounting means for the rotary conduit of the heating device; and

FIG. 3 is a fragmentary front elevational view of a modified centrifugal casting machine wherein the entire heating device is mounted on the casting arm.

Referring to the drawings, and first to FIG. 1, there is shown a centrifugal casting machine for platinum, palladium, silver, gold and similar precious metals which comprises an elongated casting arm having a first leg 11 and an opposed second leg 12. These legs extend substantially radially with reference to a rotary output shaft 13 which is fixed to a median portion of the casting arm. The shaft 13 constitutes one component of a drive means 14 here shown as a spring type motor having a strong helical torsion spring 15 which may be wound by a step-down transmission including a smaller sprocket wheel 16, a larger sprocket wheel 17 which is coaxial with the output shaft 13, an endless link chain 18 which is trained around the wheels 16, 17, and a crank handle 19 which may be manipulated by hand. A ratchet wheel 20 cooperates with a pawl 21 to prevent unwinding of the spring 15 when the shaft 13 is held against rotation by a locking device including a bracket 22 fixed to the leg 11 and having a U- shaped terminal portion 23, a latch 24 which is reciprocable in a sleeve 25 and normally extends into the terminal portion 23, and a manually operable lever 26 which is pivotally secured to an upright frame member 27. The lever 26 is connected to the latch 24 by a pin 28 and, when moved in a clockwise direction as the parts appear in FIG. 1, this lever extracts the end portion of the latch 24 from the terminal portion 23 whereby the spring 15 is free to unwind and to dissipate its energy by simultaneously rotating the arm 10 in a counterclockwise direction. The terminal portion 23 may be provided on the latch 24 to receive a portion of the bracket 22 when the arm 10 is to be held against rotation.

The transmission including the sprocket wheels 16, 17 enables the operator to rewind the spring 15 with little effort. One end of the spring is anchored in the shaft 13 and the other end of this spring is operatively connected to the larger sprocket wheel 17. The shaft 13 is accommodated in a. housing 13a which is supported by a frame member 43. This frame member also supports the pawl 21 and the shaft of the smaller sprocket wheel 16. The spring 15 must be strong enough to accelerate the shaft 13 with a minimum of delay.

The free end of the leg 11 carries an adjustable counterweight 29 which includes several detachable disks or the like so that the weight carried by the leg 12 may be accurately balanced against the weight carried by the leg 11. The casting arm 10 resembles a balance beam and is held in a horizontal or nearly horizontal position whenever the latch 24 extends into the terminal portion 23 of the bracket 22.

The leg 12 carries a platform 30 which supports a crucible 31 having a chamber 32 and provided with a passage 33 which extends substantially radially with reference to and away from the shaft 13. The platform 30 further supports a composite mold 34 of known construction which defines a mold cavity 35. The cavity 35 communicates with the chamber 32 via passage 33 so that a charge of molten metal which is accommodated in the chamber 32 is compelled to flow through the passage 33 and fills the mold cavity 35 when the spring 15 is free to rotate the arm 10. The mold 34 and the crucible 31 are mounted on suitable rails which are slidable in ways provided on the platform 30 so that the position of these parts may be regulated by an adjusting mechanism 36 of known design and not forming part of our invention.

The charge in the chamber 32 is heated by the flame produced by a heating device which is constructed and mounted in accordance with a first embodiment of our invention. The heating device includes a melting torch having a heating element in the form of a tip 37 which is adjacent to the open side of the chamber 32 and is sulficiently close to the crucible to rapidly heat the charge to melting temperature. The torch further comprises a suitably bent conduit 38 which is connected to the tip 37 and extends into the space in front of the shaft 13. A second conduit 39 is fixedly but detachably secured to the frame member 27 and is coaxial with the shaft 13. The two conduits are connected by means of a joint 40 which allows the conduit 38 to rotate about the axis of the shaft 13 so that the tip 37 remains in close proximity to the chamber 32 and heats the charge not only when the casting arm 10 is idle but also when this arm rotates to effect transfer of molten charge into the mold cavity 35. The conduit 39 is provided with two nipples 41, 42 one of which admits oxygen from a suitable tank 41a or another source and the other of which admits acetylene from a second tank 42a. In other words, the fixed conduit 39 conveys a stream of fuel to the rotary conduit 38 and the latter delivers such fuel into the tip 37 of the melting torch. The joint 40 connects the conduits 38, 39 so that the assembly including the parts 37-42 and 45, 46 may be installed or removed as a unit.

The axis of the shaft 13 is but need not be horizontal. The sleeve 25 is propped by an inclined brace 4.

The machine of FIG. 1 is operated as follows:

When the latch 24 extends into the terminal portion 23, the arm 10 is locked in a substantially horizontal plane and the operator is in a position to introduce a charge of platinum or another material to be melted into the chamber 32 of the crucible 31. The operator then opens valves 45, 45 which control the admission of oxygen and acetylene through the conduits 39, 38 and into the tip 37. The jet of fuel issuing from the orifice of the tip 37 is ignited to produce a flame which heats the charge to melting temperature. While the charge melts, the operator rotates the crank handle 19 to rewind the spring 15, but the casting arm 10 is held against rotation because the latch 24 engages the bracket 22. In order to start the casting operation, the person in charge simply manipulates the lever 26 to withdraw the latch 24 from the terminal portion 23 whereupon the arm 10 begins to spin at a high speed and the molten charge flows through the passage 33 and into the mold cavity 35. The spring 15 is strong enough to immediately accelerate the arm 10 to a very high speed so that the molten charge cannot spill through the open side or top of the chamber 32. When the casting operation is completed, the arm 10 is brought to a halt (or the spring 15 unwinds completely) and the mold 34 is detached from the platform 30 to be taken apart in order to expose the casting therein. By placing another mold onto the platform 30 and by rewinding the spring 15, the operator prepares the casting machine for the next operation.

The conduit 39 continues to deliver fuel during the entire casting operation so that the charge in the chamber 32 cannot harden prior to transfer into the cavity 35. Thus, instead of allowing for heating only at the time the casting arm 10 is idle, the machine of our invention allows for heating of the charge prior to and during actual rotation of the casting arm. This reduces the number of defective castings by insuring that the mold cavity 35 is invariably filled with material as long as the volume of the charge admitted into the chamber 32 sufiices to fill the mold.

The machine of FIG. 1 further comprises a windshield 54 which resembles a panel and consists of asbestos or another suitable heat-resistant material. This panel is mounted on the platform 30 intermediate the tip 37 and motor 14 to prevent extinction of the flame when the arm rotates and to simultaneously protect the motor from excessive heat. The panel 50 also constitutes a support for the rotary conduit 38 and is provided with an aperture 51 (see FIG. 2) which is large enough to receive the conduit 38 with at least some clearance. The means for mounting the conduit 38 on the panel 5'3 comprises a mounting ring 52 fixed to the front side of the panel so as to surround the aperture 51, and a series of radially extending resilient elements in the form of coil springs 53 which connect the mounting ring 52 with a second ring 54 on the conduit 38. Thus, the conduit 38 is free to move within the confines of the aperture 51 to compensate for any inaccuracies in the alignment of its section 38a with the axis of the conduit .39. In other words, the springs 53 will enable the conduit 38 and tip 37 to perform some movements with reference to the leg 12 and crucible 31,

Instead of utilizing the mounting of FIG. 2, the machine may be provided with a ball-and-socket coupling as a substitute for the joint 40 shown in FIG. 1.

FIG. 3 illustrates a portion of a modified centrifugal casting machine wherein the arm 10 carries the entire heating device including an oxygen tank 60, an acetylene tank 61, a conduit 62 which connects to the tanks 60, 61 and a tip 37 which corresponds to the tip 37 of the machine shown in FIGS. 1 and 2. The tanks 60, 61 replace the counterweight 29 and are longitudinally adjustably mounted on the leg 11' of the arm 10'. This simplified machine may be operated in the same way as the machine of FIG. 1, i.e., the valves 45 46 will remain open when the arm 10 is rotated by the output shaft 13' which latter forms part of a suitable drive not particularly shown in FIG. 3. The bracket 22 serves the same purpose as the bracket 22 of FIG. 1.

It is clear that the casting arm 10 or 10 may rotate in a horizontal plane.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can, by applying current knowledge, readily adapt it for various applications without omitting features which fairly constitute essential characteristics of the generic and specific aspects of this invention and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the following claims.

What is claimed as new and desired to be secured by Letters Patent is:

1. In a centrifugal casting machine, particularly in a machine for casting precious metals and similar materials, drive means including a rotary output member rotatable about a fixed axis; a casting arm fixedly secured to and having a leg extending substantially radially with reference to said output member; a mold fixed to said leg and having a cavity arranged to receive a supply of molten material, said mold being distant from said output member; a crucible mounted on said leg intermediate said mold and said output member and having a chamber communicating with said cavity, said chamber being arranged to receive a charge of material to be melted whereby, upon heating to melting temperature, said charge enters the cavity by centrifugal force in response to rotation of said arm; heating means including a melting torch having a tip mounted on and rotatable with said arm, said tip being adjacent to said crucible to produce a flame which heats said charge to melting temperature when said arm is idle and also when said arm rotates, said torch further comprising a fixed conduit coaxial with said output member, a second conduit connected with said tip, a joint connecting said conduits so that the second conduit is free to rotate with said arm, and a source of fuel connected with said fixed conduit, a windshield mounted on said leg in front of said tip to shield the flame when said arm rotates, said windshield comprising a panel having an aperture receiving with clearance a portion of said second conduit; and mounting means securing said second conduit to said panel so that said second conduit is free to move within the confines of said aperture.

2. A structure as set forth in claim 1, wherein said windshield is mounted intermediate said crucible and said output member.

3. A structure as set forth in claim 1 wherein said panel consists of heat-resistant material.

4. A structure as set forth in claim 5, wherein said mounting means comprises a mounting member fixed to said panel and resilient means connecting said mounting member with said second conduit.

5. In a centrifugal casting machine, particularly in a machine for casting precious metals and similar materials, drive means including a rotary output shaft arranged to rotate about a fixed axis; a casting arm fixedly secured to and having two opposed legs extending substantially radially with reference to said shaft; a mold fixed to one of said legs and having a cavity arranged to receive a supply of molten material, said mold being distant from said shaft; a crucible mounted on said one leg intermediate said mold and said shaft and having a chamber communicating with said cavity, said chamber being arranged to receive a charge of material to be melted whereby, upon heating to melting temperature, said charge is subjected to the action of centrifugal forces and enters said cavity when said shaft rotates said arm; and heating means including amelting torch having a tip mounted on said one leg adjacent to said crucible so that said charge may be heated by the flame which is produced by said tip not only when said arm is idle but also when said arm rotates, said heating means further comprising a source of fuel connected with the other of said legs so as to constitute a conuterweight for said mold and said crucible, and conduit means connecting said source with said tip.

References Cited UNITED STATES PATENTS 1,195,803 8/1916 Gardner 164-289 X 1,302,438 4/ 1919 Rudkin. 1,502,435 7/ 1924 Morgan 164-290 2,009,489 7/ 1935 Fritsche 164-25 8 2,338,560 1/ 1944 Yaruss 164-289 2,521,978 9/ 1950 Inger. 2,553,899 5/ 1951 Dempsey 228-59 X 2,805,456 9/ 1957 Bosna 164-154 3,199,158 8/ 1965 Rigatti-Luchini 164-258 FOREIGN PATENTS 434,612 12/1911 France.

I. SPENCER OVERHOLSER, Primary Examiner. R. S. ANNEAR, Assistant Examiner. 

1. IN A CENTRIFUGAL CASTING MACHINE, PARTICULARLY IN A MACHINE FOR CASTING PRECIOUS METALS AND SIMILAR MATERIALS, DRIVE MEANS INCLUDING A ROTARY OUTPUT MEMBER ROTATABLE ABOUT A FIXED AXIS; A CASTING ARM FIXEDLY SECURED TO AND HAVING A LEG EXTENDING SUBSTANTIALLY RADIALLY WITH REFERENCE TO SAID OUTPUT MEMBER; A MOLD FIXED TO SAID LEG AND HAVING A CAVITY ARRANGED TO RECEIVE A SUPPLY OF MOLTEN MATERIAL, AND MOLD BEING DISTANT FROM SAID OUTPUT MEMBER; A CRUCIBLE MOUNTED ON SAID LEG INTERMEDIATE SAID MOLD AND SAID OUTPUT MEMBER AND HAVING A CHAMBER COMMUNICATING WITH SAID CAVITY, SAID CHAMBER BEING ARRANGED TO RECEIVE A CHARGE OF MATERIAL TO BE MELTED WHEREBY, UPON HEATING TO MELTING TEMPERATURE, SAID CHARGE ENTERS THE CAVITY BY CENTRIFUGAL FORCE IN RESPONSE TO ROTATION OF SAID ARM; HEATING MEANS INCLUDING A MELTING TORCH HAVING A TIP MOUNTED ON SAID ROTATABLE WITH SAID ARM, SAID TIP BEING ADJACENT TO SAID CRUCIBLE TO PRODUCE A FLAME WHICH HEATS SAID CHARGE TO MELTING TEMPERATURE WHEN SAID ARM IS IDLE AND ALSO WHEN SAID ARM ROTATES, SAID TORCH FURTHER COMPRISING A FIXED CONDUIT COAXIAL WITH SAID OUTPUT MEMBER, A SECOND CONDUIT CONNECTED WITH SAID TIP, A JOINT CONNECTING SAID CONDUITS SO THAT THE SECOND CONDUIT IS FREE TO ROTATE WITH SAID ARM, AND A SOURCE OF FUEL CONNECTED WITH SAID FIXED CONDUIT, A WINDSHIELD MOUNTED ON SAID LEG IN FRONT OF SAID TIP TO SHIELD THE FLAME WHEN SAID ARM ROTATES, 